Inclusion Criteria:

- Provide signed and dated written Informed Consent

- Have been taking upfront AI adjuvant therapy in line with current SmPC

- Be capable of completing drug intake by herself

- Be capable of understanding Chinese

Exclusion Criteria:

- Upfront adjuvant hormonal therapy by an AI to which upfront adjuvant indication has
not been granted by SFDA

- Upfront adjuvant AI medication which has exceeded over eight weeks

- Previous adjuvant hormonal therapy for breast cancer lasting over 8 weeks other than
AI

- Involvement in the planning and conduct of the study (applies to both AstraZeneca
staff or staff at the study site)